JP7468346B2 - Polymers - Google Patents

Description

The present invention relates to a polymeric compound in which benzobisthiazole structural units and bithiophene structural units or cyclohexadithiophenedione structural units are arranged alternately, an organic semiconductor material comprising the polymeric compound, an organic electronic device comprising the organic semiconductor material, and a solar cell module comprising the organic electronic device.

Organic semiconductor materials are one of the most important materials in the field of organic electronics, and can be classified into p-type organic semiconductor materials that are electron donating and n-type organic semiconductor materials that are electron accepting. By appropriately combining such p-type and n-type organic semiconductor materials, various semiconductor elements can be manufactured. Semiconductor elements are used in organic electronic devices such as organic electroluminescence, which emits light by the action of excitons formed by the recombination of electrons and holes, organic thin-film solar cells that convert light into electricity, and organic thin-film transistors that control current and voltage. An example of an organic semiconductor material used in an organic electronic device is disclosed in, for example, Patent Document 1. The organic semiconductor material described in Patent Document 1 contains a polymer compound having a structural unit with a specific benzobisthiazole skeleton.

Among organic electronic devices, organic thin-film solar cells are useful for environmental conservation because they do not emit carbon dioxide into the atmosphere, and are also easy to manufacture due to their simple structure, so demand for them is increasing. It is desirable for organic thin-film solar cells to have a high efficiency in converting solar energy into electricity (photoelectric conversion efficiency η). The photoelectric conversion efficiency η is a value calculated by the product of the short-circuit current density (Jsc), the open-circuit voltage (Voc), and the fill factor (FF) [η = Jsc × Voc × FF], and in order to increase the photoelectric conversion efficiency η, it is necessary to improve either the short-circuit current density (Jsc), the open-circuit voltage (Voc), or the fill factor (FF).

WO2015/122321

Among the parameters that determine the photoelectric conversion efficiency η, the short-circuit current density (Jsc) is greatly affected by the manufacturing process when producing organic electronic devices, such as the molecular density of the organic semiconductor material, while the open circuit voltage (Voc) and fill factor (FF) are known to be greatly affected by the phase separation state of the p-type and n-type semiconductors and the molecular structure of the organic semiconductor material. Therefore, it is believed that by optimizing the molecular structure of the polymer compound that constitutes the organic semiconductor material, the product of the open circuit voltage (Voc) and the fill factor (FF) [Voc x FF] can be increased, thereby increasing the photoelectric conversion efficiency η.

An object of the present invention is to provide a polymer compound capable of increasing the photoelectric conversion efficiency η of an organic electronic device. Another object of the present invention is to provide an organic semiconductor material containing the polymer compound, an organic electronic device containing the organic semiconductor material, and a solar cell module containing the organic electronic device.

［式（１）中、Ｔ¹、Ｔ²は、それぞれ独立に、アルコキシ基であるか、チオアルコキシ基であるか、炭化水素基またはオルガノシリル基で置換されていてもよいチオフェン環であるか、炭化水素基またはオルガノシリル基で置換されていてもよいチアゾール環であるか、炭化水素基、オルガノシリル基、アルコキシ基、チオアルコキシ基、トリフルオロメチル基、またはハロゲン原子で置換されていてもよいフェニル基を表す。
また、Ｂ¹、Ｂ²は、それぞれ独立に、炭化水素基で置換されていてもよいチオフェン環であるか、炭化水素基で置換されていてもよいチアゾール環であるか、またはエチニレン基を表す。］

［式（２）中、Ｒ^aは、Ｒ^a1または＊－Ｒ^a2－Ｏ－Ｒ^a1を表す。Ｒ^a1は、炭素数６～３０の炭化水素基を表し、Ｒ^a2は、炭素数１～５の炭化水素基を表し、＊は結合手を表す。
また、Ｒ^bは、それぞれ独立に、水素原子、または炭素数１～５の炭化水素基を表す。］

［式（３）中、Ｒ^c、Ｒ^dは、それぞれ独立に、炭素数６～３０の炭化水素基を表す。］
［２］ Ｔ¹、Ｔ²が、それぞれ独立に、下記式（ｔ１）～式（ｔ５）のいずれかで表される基である［１］に記載の高分子化合物。

［式（ｔ１）～式（ｔ５）中、Ｒ¹³、Ｒ¹⁴は、それぞれ独立に、炭素数６～３０の炭化水素基を表す。
Ｒ¹⁵、Ｒ¹⁶は、それぞれ独立に、炭素数６～３０の炭化水素基、または＊－Ｓｉ（Ｒ¹⁸）₃で表される基を表す。
Ｒ¹⁷は、それぞれ独立に、炭素数６～３０の炭化水素基、＊－Ｓｉ（Ｒ¹⁸）₃、＊－Ｏ－Ｒ¹⁹、＊－Ｓ－Ｒ²⁰、＊－ＣＦ₃、またはハロゲン原子を表す。
ｎ１は１～３の整数、ｎ２は１または２、ｎ３は１～５の整数をそれぞれ表し、複数のＲ¹⁵は同一でも異なっていてもよく、複数のＲ¹⁶は同一でも異なっていてもよく、複数のＲ¹⁷は同一でも異なっていてもよい。
Ｒ¹⁸は、それぞれ独立に、炭素数１～２０の脂肪族炭化水素基、または炭素数６～１０の芳香族炭化水素基を表し、複数のＲ¹⁸は同一でも異なっていてもよい。
Ｒ¹⁹、Ｒ²⁰は、それぞれ独立に、炭素数６～３０の炭化水素基を表す。
＊は、結合手を表す。］
［３］ Ｂ¹、Ｂ²が、それぞれ独立に、下記式（ｂ１）～式（ｂ３）のいずれかで表される基である［１］または［２］に記載の高分子化合物。

［式（ｂ１）～式（ｂ３）中、Ｒ²¹、Ｒ²²は、それぞれ独立に、炭素数６～３０の炭化水素基を表す。
ｎ４は０～２の整数、ｎ５は０または１を表し、複数のＲ²¹は同一でも異なっていてもよい。
＊は、結合手を表し、左側の＊は、ベンゾビスチアゾール構造単位のベンゼン環に結合する結合手を表す。］
［４］ ドナー－アクセプター型半導体高分子化合物である［１］～［３］のいずれかに記載の高分子化合物。
［５］ ［１］～［４］のいずれかに記載の高分子化合物を含むことを特徴とする有機半導体材料。
［６］ ［５］に記載の有機半導体材料を含むことを特徴とする有機電子デバイス。
［７］ 有機薄膜太陽電池である［６］に記載の有機電子デバイス。
［８］ ［７］に記載の有機電子デバイスを含むことを特徴とする太陽電池モジュール。 The present invention includes the following inventions.
[1] A polymer compound characterized in that a benzobisthiazole structural unit represented by the following formula (1) and a bithiophene structural unit represented by the following formula (2) or a cyclohexadithiophenedione structural unit represented by the following formula (3) are arranged alternately.

[In formula (1), T ¹ and T ² each independently represent an alkoxy group, a thioalkoxy group, a thiophene ring which may be substituted with a hydrocarbon group or an organosilyl group, a thiazole ring which may be substituted with a hydrocarbon group or an organosilyl group, or a hydrocarbon group, an organosilyl group, an alkoxy group, a thioalkoxy group, a trifluoromethyl group, or a phenyl group which may be substituted with a halogen atom.
Furthermore, B ¹ and B ² each independently represent a thiophene ring which may be substituted with a hydrocarbon group, a thiazole ring which may be substituted with a hydrocarbon group, or an ethynylene group.]

In formula (2), R ^a represents R ^a1 or *-R ^a2 -O-R ^a1 . R ^a1 represents a hydrocarbon group having 6 to 30 carbon atoms, R ^a2 represents a hydrocarbon group having 1 to 5 carbon atoms, and * represents a bond.
Each R ^b independently represents a hydrogen atom or a hydrocarbon group having 1 to 5 carbon atoms.

[In formula (3), R ^c and R ^d each independently represent a hydrocarbon group having 6 to 30 carbon atoms.]
[2] The polymer compound according to [1], wherein T ¹ and T ² are each independently a group represented by any one of the following formulas (t1) to (t5):

In formulae (t1) to (t5), R ¹³ and R ¹⁴ each independently represent a hydrocarbon group having 6 to 30 carbon atoms.
R ¹⁵ and R ¹⁶ each independently represent a hydrocarbon group having 6 to 30 carbon atoms or a group represented by *-Si(R ¹⁸ ) ₃ .
R ¹⁷ each independently represents a hydrocarbon group having 6 to 30 carbon atoms, *-Si(R ¹⁸ ) ₃ , *-O-R ¹⁹ , *-S-R ²⁰ , *-CF ₃ or a halogen atom.
n1 represents an integer of 1 to 3, n2 represents 1 or 2, and n3 represents an integer of 1 to 5; multiple R ^15s may be the same or different, multiple R ^16s may be the same or different, and multiple R ^17s may be the same or different.
Each R ¹⁸ independently represents an aliphatic hydrocarbon group having 1 to 20 carbon atoms or an aromatic hydrocarbon group having 6 to 10 carbon atoms, and multiple R ¹⁸ may be the same or different.
R ¹⁹ and R ²⁰ each independently represent a hydrocarbon group having 6 to 30 carbon atoms.
* represents a bond.
[3] The polymer compound according to [1] or [ ² ], wherein B ¹ and B 2 are each independently a group represented by any one of the following formulas (b1) to (b3):

In formulae (b1) to (b3), R ²¹ and R ²² each independently represent a hydrocarbon group having 6 to 30 carbon atoms.
n4 represents an integer of 0 to 2, n5 represents 0 or 1, and multiple R ²¹ may be the same or different.
* represents a bond, and the * on the left represents a bond bonded to the benzene ring of the benzobisthiazole structural unit.
[4] The polymer compound according to any one of [1] to [3], which is a donor-acceptor type semiconducting polymer compound.
[5] An organic semiconductor material comprising the polymer compound according to any one of [1] to [4].
[6] An organic electronic device comprising the organic semiconductor material according to [5].
[7] The organic electronic device according to [6], which is an organic thin-film solar cell.
[8] A solar cell module comprising the organic electronic device according to [7].

The polymer compound of the present invention has a specific benzobisthiazole structural unit and a specific bithiophene structural unit or a specific cyclohexadithiophenedione structural unit arranged alternately. By using an organic semiconductor material containing this polymer compound, the photoelectric conversion efficiency η of an organic electronic device can be increased. In addition, according to the present invention, it is possible to provide an organic semiconductor material containing the above polymer compound, an organic electronic device containing the organic semiconductor material, and a solar cell module containing the organic electronic device.

The present inventors have conducted intensive research to solve the above problems. As a result, they have discovered that in order to increase the product [Voc × FF] of the open circuit voltage (Voc) and the fill factor (FF) in order to increase the photoelectric conversion efficiency η of an organic electronic device, it is sufficient to make the molecular structure of a polymer compound a structure in which a specific benzobisthiazole structural unit and a specific bithiophene structural unit or a specific cyclohexadithiophenedione structural unit are alternately arranged, and to fabricate an organic electronic device using an organic semiconductor material containing this polymer compound, thereby completing the present invention.

The present invention is described in detail below.

The polymer compound of the present invention is characterized in that benzobisthiazole structural units represented by the following formula (1) and bithiophene structural units represented by the following formula (2) or cyclohexadithiophenedione structural units represented by the following formula (3) are arranged alternately.

In the above formula (1), ^T1 and ^T2 each independently represent an alkoxy group, a thioalkoxy group, a thiophene ring which may be substituted with a hydrocarbon group or an organosilyl group, a thiazole ring which may be substituted with a hydrocarbon group or an organosilyl group, a hydrocarbon group, an organosilyl group, an alkoxy group, a thioalkoxy group, a trifluoromethyl group, or a phenyl group which may be substituted with a halogen atom. Also, ^B1 and ^B2 each independently represent a thiophene ring which may be substituted with a hydrocarbon group, a thiazole ring which may be substituted with a hydrocarbon group, or an ethynylene group.

In the above formula (2), R ^a represents R ^a1 or *-R ^a2 -O-R ^a1 . R ^a1 represents a hydrocarbon group having 6 to 30 carbon atoms, R ^a2 represents a hydrocarbon group having 1 to 5 carbon atoms, and * represents a bond. Each R ^b independently represents a hydrogen atom or a hydrocarbon group having 1 to 5 carbon atoms.

In the above formula (3), R ^c and R ^d each independently represent a hydrocarbon group having 6 to 30 carbon atoms.

The above polymer compound has an optimized molecular structure, which makes it possible to increase the product [Voc x FF] of the open circuit voltage (Voc) and the fill factor (FF), which are influenced by the organic semiconductor material and are among the factors that determine the photoelectric conversion efficiency η of an organic electronic device. As a result, the photoelectric conversion efficiency η can be increased and the output can be stabilized.

[Benzobisthiazole structural unit]
In the benzobisthiazole structural unit represented by the above formula (1), ^T1 and ^T2 each independently represent an alkoxy group, a thioalkoxy group, a thiophene ring, a thiazole ring, or a phenyl group. The thiophene ring may be substituted with a hydrocarbon group or an organosilyl group, the thiazole ring may be substituted with a hydrocarbon group or an organosilyl group, and the phenyl group may be substituted with a hydrocarbon group, an organosilyl group, an alkoxy group, a thioalkoxy group, a trifluoromethyl group, or a halogen atom. Any of fluorine, chlorine, bromine, and iodine can be used as the halogen atom.

The above organosilyl group means a monovalent group in which one or more hydrocarbon groups are substituted on a Si atom, and the number of hydrocarbon groups substituted on the Si atom is preferably two or more, and more preferably three.

The above T ¹ and T ² may be the same or different from each other, but from the viewpoint of ease of production, it is preferable that they are the same.

The above T ¹ and T ² are preferably each independently a group represented by any one of the following formulas (t1) to (t5). That is, the alkoxy group represented by the above T ¹ and T ² is preferably a group represented by the following formula (t1), the thioalkoxy group represented by the above T ¹ and T ² is preferably a group represented by the following formula (t2), the thiophene ring represented by the above T ¹ and T ² is preferably a group represented by the following formula (t3), the thiazole ring represented by the above T ¹ and T ² is preferably a group represented by the following formula (t4), and the phenyl group represented by the above T ¹ and T ² is preferably a group represented by the following formula (t5). When the above T ¹ and T ² are a group represented by any one of the following formulas (t1) to (t5), it is possible to absorb light of a short wavelength and have high planarity, so that π-π stacking is efficiently formed, and the photoelectric conversion efficiency η can be further increased.

In the above formulae (t1) to (t5), R ¹³ and R ¹⁴ each independently represent a hydrocarbon group having 6 to 30 carbon atoms. R ¹⁵ and R ¹⁶ each independently represent a hydrocarbon group having 6 to 30 carbon atoms, or a group represented by *-Si(R ¹⁸ ) _3. R ¹⁷ each independently represent a hydrocarbon group having 6 to 30 carbon atoms, *-Si(R ¹⁸ ) ₃ , *-O-R ¹⁹ , *-S-R ²⁰ , *-CF ₃ , or a halogen atom. n1 represents an integer of 1 to 3, n2 represents 1 or 2, and n3 represents an integer of 1 to 5, and multiple R ^15s may be the same or different, multiple R ^16s may be the same or different, and multiple R ^17s may be the same or different. Each R ¹⁸ independently represents an aliphatic hydrocarbon group having 1 to 20 carbon atoms or an aromatic hydrocarbon group having 6 to 10 carbon atoms, and multiple R ¹⁸ may be the same or different. Each R ¹⁹ and R ²⁰ independently represents a hydrocarbon group having 6 to 30 carbon atoms. * represents a bond.

In the above formulas (t1) to (t5), the hydrocarbon group having 6 to 30 carbon atoms represented by R ¹³ to R ¹⁷ is preferably a branched hydrocarbon group, more preferably a branched saturated hydrocarbon group. By having a branch in the hydrocarbon group represented by R ¹³ to R ¹⁷ , the solubility in organic solvents can be increased, and the polymer compound of the present invention can obtain appropriate crystallinity.

The larger the number of carbon atoms in the hydrocarbon group represented by R ¹³ to R ¹⁷ , the more the solubility in organic solvents can be improved, but if the number is too large, the reactivity in the coupling reaction described below decreases, making it difficult to synthesize a polymer compound. Therefore, the number of carbon atoms in the hydrocarbon group represented by R ¹³ to R ¹⁷ is preferably 6 to 30, more preferably 8 to 25, even more preferably 8 to 20, and particularly preferably 8 to 16.

Specific examples of the hydrocarbon groups represented by R ¹³ to R ¹⁷ include alkyl groups having 6 carbon atoms, such as an n-hexyl group; alkyl groups having 7 carbon atoms, such as an n-heptyl group; alkyl groups having 8 carbon atoms, such as an n-octyl group, 1-n-butylbutyl group, 1-n-propylpentyl group, 1-ethylhexyl group, 2-ethylhexyl group, 3-ethylhexyl group, 4-ethylhexyl group, 1-methylheptyl group, 2-methylheptyl group, 6-methylheptyl group, 2,4,4-trimethylpentyl group, and 2,5-dimethylhexyl group; alkyl groups having 8 carbon atoms, such as an n-nonyl group, 1-n-propylhexyl group, 2-n-propylhexyl group, 1-ethylheptyl group, 2-ethylheptyl group, 1-methyloctyl group, 2-methyloctyl group, 6-methyloctyl group, 2,3,3 alkyl groups having 9 carbon atoms, such as n-decyl, 1-n-pentylpentyl, 1-n-butylhexyl, 2-n-butylhexyl, 1-n-propylheptyl, 1-ethyloctyl, 2-ethyloctyl, 1-methylnonyl, 2-methylnonyl, and 3,7-dimethyloctyl; alkyl groups having 10 carbon atoms, such as n-undecyl, 1-n-butylheptyl, 2-n-butylheptyl, 1-n-propyloctyl, 2-n-propyloctyl, 1-ethylnonyl, and 2-ethylnonyl; alkyl groups having 11 carbon atoms, such as n-dodecyl, 1-n-pentylheptyl, 2-n-pentylheptyl, 1-n-butyl alkyl groups having 12 carbon atoms, such as n-tridecyl group, 1-n-pentyloctyl group, 2-n-pentyloctyl group, 1-n-butylnonyl group, 2-n-butylnonyl group, 1-methyldodecyl group, 2-methyldodecyl group, etc.; alkyl groups having 13 carbon atoms, such as n-tetradecyl group, 1-n-heptylheptyl group, 1-n-hexyloctyl group, 2-n-hexyloctyl group, 1-n-pentylnonyl group, 2-n-pentylnonyl group, etc.; alkyl groups having 14 carbon atoms, such as n-pentadecyl group, 1-n-heptyloctyl group, 1-n-hexylnonyl group, 2-n-hexylnonyl group, etc.; alkyl groups having 15 carbon atoms, such as n-pentadecyl group, 1-n-heptyloctyl group, 1-n-hexylnonyl group, 2-n-hexylnonyl group, etc.; alkyl groups having 16 carbon atoms, such as a decyl group, a 2-n-hexyldecyl group, a 1-n-octyloctyl group, a 1-n-heptylnonyl group, and a 2-n-heptylnonyl group; alkyl groups having 17 carbon atoms, such as an n-heptadecyl group and a 1-n-octylnonyl group; alkyl groups having 18 carbon atoms, such as an n-octadecyl group and a 1-n-nonylnonyl group; alkyl groups having 19 carbon atoms, such as an n-nonadecyl group; alkyl groups having 20 carbon atoms, such as an n-eicosyl group and a 2-n-octyldodecyl group; alkyl groups having 21 carbon atoms, such as an n-heneicosyl group; alkyl groups having 22 carbon atoms, such as an n-docosyl group; alkyl groups having 23 carbon atoms, such as an n-tricosyl group; alkyl groups having 24 carbon atoms, such as an n-tetracosyl group and a 2-n-decyltetradecyl group; and the like. Among these, particularly preferred are 2-ethylhexyl, 3,7-dimethyloctyl, 2-n-butyloctyl, 2-n-hexyldecyl, 2-n-octyldodecyl and 2-n-decyltetradecyl groups. When the hydrocarbon groups represented by R ¹³ to R ¹⁷ are the above groups, the polymer compound of the present invention has improved solubility in organic solvents and appropriate crystallinity. The hydrocarbon groups represented by R ¹³ to R ¹⁷ are particularly preferably branched alkyl groups having 8 to 16 carbon atoms.

In the above formulas (t3) to (t5), R ¹⁸ in the group *-Si(R ¹⁸ ) ₃ represented by R ¹⁵ to R ¹⁷ each independently represents an aliphatic hydrocarbon group having 1 to 20 carbon atoms or an aromatic hydrocarbon group having 6 to 10 carbon atoms, and multiple R ¹⁸ may be the same or different. When R ¹⁵ to R ¹⁷ are groups represented by *-Si(R ¹⁸ ) ₃ , the polymer compound of the present invention has improved solubility in organic solvents.

The halogen atom represented by R ¹⁷ is preferably fluorine, chlorine, bromine or iodine.

The number of carbon atoms in the aliphatic hydrocarbon group represented by R ¹⁸ is preferably 1 to 18, and more preferably 1 to 8. Examples of the aliphatic hydrocarbon group represented by R ¹⁸ include methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, isobutyl, n-pentyl, tert-pentyl, isopentyl, n-hexyl, n-heptyl, n-octyl, 2-ethylhexyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, 2-octylbutyl, n-tridecyl, n-tetradecyl, n-pentadecyl, n-hexadecyl, 2-hexadecyl, n-heptadecyl, and octadecyl groups. The number of carbon atoms in the aromatic hydrocarbon group represented by ^{R 18} is preferably 6 to 8, more preferably 6 or 7, and particularly preferably 6. Examples of aromatic hydrocarbon groups represented by R ¹⁸ include a phenyl group, etc. Among them, R ¹⁸ is preferably an aliphatic hydrocarbon group having 1 to 20 carbon atoms, more preferably a branched aliphatic hydrocarbon group having 1 to 20 carbon atoms, and particularly preferably an isopropyl group.

A plurality of R ¹⁸ may be the same or different, but it is preferable that they are the same.

In the above formulas (t3) to (t5), specific examples of the *-Si( ^R ) ₃ group represented by R ¹⁵ to R ¹⁷ include alkylsilyl groups such as trimethylsilyl group, ethyldimethylsilyl group, isopropyldimethylsilyl group, triisopropylsilyl group, tert-butyldimethylsilyl group, triethylsilyl group, triisobutylsilyl group, tripropylsilyl group, tributylsilyl group, dimethylphenylsilyl group, and methyldiphenylsilyl group; arylsilyl groups such as triphenylsilyl group and tert-butylchlorodiphenylsilyl group; and the like. Among these, alkylsilyl groups are preferred, and trimethylsilyl group or triisopropylsilyl group is particularly preferred.

In the above formula (t5), R ¹⁹ and R ²⁰ in the group *-O-R ¹⁹ or *-S-R ²⁰ represented by R ¹⁷ each independently represent a hydrocarbon group having 6 to 30 carbon atoms, and as the hydrocarbon group having 6 to 30 carbon atoms, the groups exemplified as the hydrocarbon group having 6 to 30 carbon atoms represented by R ¹³ to R ¹⁷ above can be preferably used.

In the above formula (t3), the multiple R ¹⁵ may be the same or different, but are preferably the same. n1 is preferably 1 or 2, and more preferably 1.

In the above formula (t4), the multiple R ¹⁶ may be the same or different, but are preferably the same.

In the above formula (t5), the multiple R ¹⁷ may be the same or different, but are preferably the same. n3 is preferably an integer of 1 to 3, more preferably 1 or 2, and even more preferably 1.

As T ¹ and T ² , an electron donating group or an electron withdrawing group can be used.

Examples of electron-donating groups include groups represented by any of the following formulas (t1) to (t3).

In the above formulas (t1) to (t3), * represents a bond bonded to the thiazole ring of the benzobisthiazole structural unit.

The above R ¹³ to R ¹⁵ represent the same groups as defined above. n1 has the same meaning as defined above.

As the electron-donating group, from the viewpoint of excellent planarity of the structural unit represented by the above formula (1) as a whole, a group represented by the above formula (t1) or the above formula (t3) is more preferable, a group represented by the above formula (t3) is even more preferable, and a group represented by the following formulas (t3-1) to (t3-16) is particularly preferable. In the following formulas (t3-1) to (t3-16), * represents a bond.

Examples of electron-withdrawing groups include groups represented by the following formula (t4) or the following formula (t5).

In the above formulas (t4) and (t5), * represents a bond bonded to the thiazole ring of the benzobisthiazole structural unit.

R ¹⁶ and R ¹⁷ are the same as those defined above. n2 and n3 are the same as those defined above.

In the benzobisthiazole structural unit represented by the above formula (1), ^B1 and ^B2 each independently represent a thiophene ring, a thiazole ring, or an ethynylene group. The thiophene ring may be substituted with a hydrocarbon group, and the thiazole ring may be substituted with a hydrocarbon group.

The above B ¹ and B ² may be the same or different from each other, but from the viewpoint of ease of production, it is preferable that they are the same.

The above B ¹ and B ² are preferably each independently a group represented by any one of the following formulas (b1) to (b3). That is, the thiophene ring represented by the above B ¹ and B ² is preferably a group represented by the following formula (b1), the thiazole ring represented by the above B ¹ and B ² is preferably a group represented by the following formula (b2), and the ethynylene group represented by the above B ¹ and B ² is preferably a group represented by the following formula (b3). When the above B ¹ and B ² are groups represented by the following formulas (b1) and (b2), the benzobisthiazole structural unit represented by the above formula (1) has excellent planarity as a whole, and the obtained polymer compound has excellent planarity as a whole. In addition, when the above B ¹ and B ² are groups represented by the following formulas (b1) and (b2), an interaction between an S atom and an N atom occurs in the benzobisthiazole structural unit, and the planarity is further improved. As a result, the photoelectric conversion efficiency η can be further increased.

In the above formulas (b1) to (b3), R ²¹ and R ²² each independently represent a hydrocarbon group having 6 to 30 carbon atoms. n4 represents an integer of 0 to 2, n5 represents 0 or 1, and multiple R ²¹ may be the same or different. * represents a bond, and the * on the left represents a bond bonded to the benzene ring of the benzobisthiazole structural unit.

In the above formula (b1) and formula (b2), it is preferable that R ²¹ and R ²² are hydrocarbon groups having 6 to 30 carbon atoms, since this may further increase the photoelectric conversion efficiency η.

In the above formulas (b1) and (b2), as the hydrocarbon group having 6 to 30 carbon atoms represented by R ²¹ and R ²² , the groups exemplified as the hydrocarbon group having 6 to 30 carbon atoms represented by R ¹³ to R ¹⁷ above can be preferably used.

In the above formula (b1), the multiple R ²¹ may be the same or different, but are preferably the same. n4 is preferably 0 or 1, and more preferably 0. When n4 is 0, it is preferable because it is easy to form a donor-acceptor type semiconducting polymer.

In the above formula (b2), n5 is preferably 0. When n5 is 0, it is preferable because it is easy to form a donor-acceptor type semiconducting polymer.

Specific examples of the benzobisthiazole structural unit represented by the above formula (1) include structural units represented by the following formulas (1-1) to (1-48).

[Bithiophene structural unit]
In the bithiophene structural unit represented by the above formula (2), R ^a represents R ^a1 or *-R ^a2 -O-R ^a1 .

R ^a1 represents a hydrocarbon group having 6 to 30 carbon atoms, and R ^a2 represents a hydrocarbon group having 1 to 5 carbon atoms.

The hydrocarbon group having 6 to 30 carbon atoms represented by R ^a1 may be a linear hydrocarbon group or a branched hydrocarbon group, preferably a branched hydrocarbon group, more preferably a branched saturated hydrocarbon group. By having a branch in the hydrocarbon group represented by R ^a1 , the solubility in organic solvents can be increased, and the polymer compound of the present invention can obtain appropriate crystallinity.

The larger the number of carbon atoms in the hydrocarbon group represented by R ^a1 , the more the solubility in organic solvents can be improved, but if the number is too large, the reactivity in the coupling reaction described below decreases, making it difficult to synthesize a polymer compound. Therefore, the number of carbon atoms in the hydrocarbon group represented by R ^a1 is preferably 6 to 30, more preferably 8 to 25, even more preferably 8 to 20, and particularly preferably 8 to 16. Specific examples of the hydrocarbon group represented by R ^a1 include the groups exemplified as the hydrocarbon groups represented by R ¹³ to R ¹⁷ above. The same applies to the preferred groups.

The hydrocarbon group having 1 to 5 carbon atoms represented by R ^a2 may be a linear hydrocarbon group or a branched hydrocarbon group, and a linear hydrocarbon group is preferred. By having the hydrocarbon group represented by R ^a2 be linear, it is believed that the molecular arrangement becomes regular, resulting in improved performance.

The larger the carbon number of the hydrocarbon group represented by R ^a2 , the more the solubility in organic solvents can be improved, but if it is too large, the reactivity in the coupling reaction described below decreases, making it difficult to synthesize a polymer compound. Therefore, the carbon number of the hydrocarbon group represented by R ^a2 is preferably 1 to 5, more preferably 3 to 5, and even more preferably 4 or 5.

The hydrocarbon group having 1 to 5 carbon atoms represented by R ^a2 is preferably an aliphatic hydrocarbon group, and examples thereof include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a tert-butyl group, an isobutyl group, an n-pentyl group, a tert-pentyl group, and an isopentyl group.

In the bithiophene structural unit represented by the above formula (2), each R ^b independently represents a hydrogen atom or a hydrocarbon group having 1 to 5 carbon atoms.

The hydrocarbon group having 1 to 5 carbon atoms represented by R ^b is preferably an aliphatic hydrocarbon group, and examples thereof include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a tert-butyl group, an isobutyl group, an n-pentyl group, a tert-pentyl group, and an isopentyl group.

[Cyclohexadithiophenedione structural unit]
In the cyclohexadithiophenedione structural unit represented by the above formula (3), R ^c and R ^d each independently represent a hydrocarbon group having 6 to 30 carbon atoms.

The hydrocarbon group having 6 to 30 carbon atoms represented by ^Rc and ^Rd may be a linear hydrocarbon group or a branched hydrocarbon group, preferably a branched hydrocarbon group, more preferably a branched saturated hydrocarbon group. By having a branch in the hydrocarbon group represented by ^Rc and ^Rd , the solubility in organic solvents can be increased, and the polymer compound of the present invention can obtain an appropriate crystallinity.

The larger the carbon number of the hydrocarbon group represented by R ^c and R ^d , the more the solubility in organic solvents can be improved, but if it is too large, the reactivity in the coupling reaction described below decreases, making it difficult to synthesize a polymer compound. Therefore, the carbon number of the hydrocarbon group represented by R ^c and R ^d is preferably 6 to 30. The carbon number of the hydrocarbon group represented by R ^c and R ^d is more preferably 8 or more, more preferably 25 or less, even more preferably 20 or less, particularly preferably 16 or less, and most preferably 11 or less.

Specific examples of the hydrocarbon group represented by R ^c and R ^d include the groups exemplified as the hydrocarbon groups represented by R ¹³ to R ¹⁷ above. The same also applies to the preferred groups.

The weight average molecular weight (Mw) of the polymer compound of the present invention is generally 2000 or more and 500,000 or less, more preferably 3000 or more and 200,000 or less. The number average molecular weight (Mn) of the polymer compound of the present invention is generally 2000 or more and 500,000 or less, more preferably 3000 or more and 200,000 or less. The weight average molecular weight (Mw) and number average molecular weight (Mn) of the polymer compound of the present invention can be calculated based on a calibration curve prepared using gel permeation chromatography and polystyrene as a standard sample.

By using an organic semiconductor material containing a polymer compound in which the benzobisthiazole structural unit represented by the above formula (1) and the bithiophene structural unit represented by the above formula (2) or the cyclohexadithiophenedione structural unit represented by the above formula (3) are alternately arranged, the product [Voc x FF] of the open circuit voltage (Voc) and the fill factor (FF) can be increased, thereby increasing the photoelectric conversion efficiency η of the organic electronic device. In particular, the photoelectric conversion efficiency η of the organic electronic device can be further increased by using an organic semiconductor material containing a polymer compound in which the benzobisthiazole structural unit represented by the above formula (1) and the bithiophene structural unit represented by the above formula (2) are alternately arranged, rather than a polymer compound in which the benzobisthiazole structural unit represented by the above formula (1) and the cyclohexadithiophenedione structural unit represented by the above formula (3) are alternately arranged.

The polymer compound of the present invention is preferably a donor-acceptor type semiconducting polymer compound. A donor-acceptor type semiconducting polymer compound refers to a polymer compound in which donor units and acceptor units are arranged alternately. A donor unit refers to an electron-donating structural unit, and an acceptor unit refers to an electron-accepting structural unit.

The present invention also includes an organic semiconductor material containing the above polymer compound. When the organic semiconductor material containing the above polymer compound is used, particularly as a p-type organic semiconductor material, charge separation can be easily caused between the p-type organic semiconductor and the n-type organic semiconductor, and the photoelectric conversion efficiency η of the organic electronic device can be increased.

The present invention also includes organic electronic devices containing the organic semiconductor material. Examples of organic electronic devices include organic thin-film solar cells, and other examples include organic EL devices, organic lasers, organic photodetectors, organic transistors, and organic sensors. The organic thin-film solar cells can be used for any purpose, and examples of fields in which the organic thin-film solar cells can be applied include solar cells for building materials, solar cells for automobiles, solar cells for interior decoration, solar cells for railways, solar cells for ships, solar cells for airplanes, solar cells for spacecraft, solar cells for home appliances, solar cells for mobile phones, and solar cells for toys.

The present invention also includes a solar cell module including an organic electronic device that is an organic thin-film solar cell. That is, the present invention may include a solar cell module in which the organic thin-film solar cell is placed on a substrate. As a specific example, when a building material board is used as the substrate, a solar cell panel can be produced as a solar cell module by providing an organic thin-film solar cell on the surface of the board.

Next, a method for producing the polymer compound of the present invention will be described.

The polymer compound of the present invention can be produced by alternately arranging the benzobisthiazole structural unit represented by the above formula (1) and the bithiophene structural unit represented by the above formula (2) or the cyclohexadithiophenedione structural unit represented by the above formula (3). The benzobisthiazole structural unit represented by the above formula (1) and the bithiophene structural unit represented by the above formula (2) or the cyclohexadithiophenedione structural unit represented by the above formula (3) can be alternately arranged by a coupling reaction.

The compound having the benzobisthiazole structural unit represented by the above formula (1) can be produced, for example, by the method described in WO2015/122321.

The compound having the bithiophene structural unit represented by the above formula (2) can be prepared, for example, by using "Dithieno[3,2-c:2',3'-e]oxepine-4,6-dione (D4972)" manufactured by Tokyo Chemical Industry Co., Ltd. as a raw material, according to the method described in Journal of the American Chemical Society, Vol. 134, pp. 18427-18439, published in 2012.

Compounds having the cyclohexadithiophenedione structural unit represented by the above formula (3) can be any known compound, such as "1,3-dibromo-5,7-bis(2-ethylhexyl)benzo[1,2-c:4,5-c']dithiophene-4,8-dione (184533)" manufactured by Chem Shuttle.

The coupling reaction can be carried out by reacting a compound having a benzobisthiazole structural unit represented by the above formula (1) with a halide of a compound having a bithiophene structural unit represented by the above formula (2) or a halide of a compound having a cyclohexadithiophenedione structural unit represented by the above formula (3) in the presence of a metal catalyst.

The molar ratio of the compound having the benzobisthiazole structural unit represented by the above formula (1) to the halide of the compound having the bithiophene structural unit represented by the above formula (2) is preferably in the range of 1:99 to 99:1, more preferably in the range of 20:80 to 80:20, and even more preferably in the range of 40:60 to 60:40.

The molar ratio of the compound having the benzobisthiazole structural unit represented by the above formula (1) to the halide of the compound having the cyclohexadithiophenedione structural unit represented by the above formula (3) is preferably in the range of 1:99 to 99:1, more preferably in the range of 20:80 to 80:20, and even more preferably in the range of 40:60 to 60:40.

The metal catalyst is preferably a transition metal catalyst, and examples of the transition metal catalyst include palladium-based catalysts, nickel-based catalysts, iron-based catalysts, copper-based catalysts, rhodium-based catalysts, and ruthenium-based catalysts. Among these, palladium-based catalysts are preferred. The palladium in the palladium-based catalyst may be zero-valent or divalent.

Examples of the palladium catalyst include palladium chloride (II), palladium bromide (II), palladium iodide (II), palladium oxide (II), palladium sulfide (II), palladium telluride (II), palladium hydroxide (II), palladium selenide (II), palladium cyanide (II), palladium acetate (II), palladium trifluoroacetate (II), palladium acetylacetonate (II), diacetate bis(triphenylphosphine)palladium (II), tetrakis(triphenylphosphine)palladium (0), dichlorobis(triphenylphosphine)palladium (II), dichlorobis(acetonitrile)palladium (II), dichlorobis(benzonitrile)palladium (II), dichloro[1,2-bis(diphenylphosphino)ethane]palladium (II), dichloro[1,3-bis(diphenylphosphino)propane]palladium (II), dichloro[1,4-bis(diphenylphosphino)propane]palladium (II), bis(diphenylphosphino)butane]palladium(II), dichloro[1,1-bis(diphenylphosphinoferrocene)]palladium(II), dichloro[1,1-bis(diphenylphosphino)ferrocene]palladium(II) dichloromethane adduct, bis(dibenzylideneacetone)palladium(0), tris(dibenzylideneacetone)dipalladium(0), tris(dibenzylideneacetone)dipalladium(0)-chloroform adduct, dichloro[1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene](3-chloropyridyl)palladium(II), bis(tri-tert-butylphosphine)palladium(0), dichloro[2,5-norbornadiene]palladium(II), dichlorobis(ethylenediamine)palladium(II), dichloro(1,5-cyclooctadiene)palladium(II), dichlorobis(methyldiphenylphosphine)palladium(II), and the like. These catalysts may be used alone or in combination of two or more. Among these, dichlorobis(triphenylphosphine)palladium(II), tris(dibenzylideneacetone)dipalladium(0), and tris(dibenzylideneacetone)dipalladium(0)-chloroform adduct are particularly preferred.

In the above coupling reaction, the molar ratio of the compound having the benzobisthiazole structural unit represented by the above formula (1) to the metal catalyst [compound having the benzobisthiazole structural unit represented by the above formula (1):metal catalyst] is generally about 1:0.0001 to 1:0.5 and is not particularly limited, but from the viewpoint of yield and reaction efficiency, it is preferably 1:0.001 to 1:0.3, more preferably 1:0.005 to 1:0.2, and even more preferably 1:0.01 to 1:0.1.

In the above coupling reaction, a ligand may be coordinated to the metal catalyst. Examples of the ligand include trimethylphosphine, triethylphosphine, tri(n-butyl)phosphine, tri(isopropyl)phosphine, tri(tert-butyl)phosphine, tri-tert-butylphosphonium tetrafluoroborate, bis(tert-butyl)methylphosphine, tricyclohexylphosphine, diphenyl(methyl)phosphine, triphenylphosphine, tris(o-tolyl)phosphine, tris(m-tolyl)phosphine, tris(p-tolyl)phosphine, tris(2-furyl)phosphine, tris(2-methoxyphenyl)phosphine, and the like. phosphine, tris(3-methoxyphenyl)phosphine, tris(4-methoxyphenyl)phosphine, 2-dicyclohexylphosphinobiphenyl, 2-dicyclohexylphosphino-2'-methylbiphenyl, 2-dicyclohexylphosphino-2',4',6'-triisopropyl-1,1'-biphenyl, 2-dicyclohexylphosphino-2',6'-dimethoxy-1,1'-biphenyl, 2-dicyclohexylphosphino-2'-(N,N'-dimethylamino)biphenyl, 2-diphenylphosphino-2'-(N,N'-dimethylamino)biphenyl, 2-(di-t 1,2-bis(diphenylphosphino)ethane, 1,3-bis(diphenylphosphino)propane, 1,4-bis(diphenylphosphino)butane, 1,2-bis(dicyclohexylphosphino)ethane, 1,3-bis(dicyclohexylphosphino)propane, 1,4-bis(dicyclohexylphosphino)butane, 1,2-bis(diphenylphosphinoethylene, 1,2-bis(diphenylphosphino)ethylene, 1,3-bis(dicyclohexylphosphino)propane, 1,4-bis(dicyclohexylphosphino)butane, 1,2-bis(diphenylphosphinoethylene), , 1'-bis(diphenylphosphino)ferrocene, 1,2-ethylenediamine, N,N,N',N'-tetramethylethylenediamine, 2,2'-bipyridyl, 1,3-diphenyldihydroimidazolylidene, 1,3-dimethyldihydroimidazolylidene, diethyldihydroimidazolylidene, 1,3-bis(2,4,6-trimethylphenyl)dihydroimidazolylidene, 1,3-bis(2,6-diisopropylphenyl)dihydroimidazolylidene, 1,10-phenanthroline, 5,6-dimethyl-1,10-phenanthroline, bathophenanthroline, etc. The above ligands may be used alone or in combination of two or more kinds. Among them, triphenylphosphine, tris(o-tolyl)phosphine, tris(2-furyl)phosphine, and tris(2-methoxyphenyl)phosphine are preferred.

When the ligand is coordinated to the metal catalyst during the coupling reaction, the molar ratio of the metal catalyst to the ligand (metal catalyst:ligand) is generally about 1:0.5 to 1:10 and is not particularly limited, but from the standpoint of yield and reaction efficiency, 1:1 to 1:8 is preferred, 1:1 to 1:7 is more preferred, and 1:1 to 1:5 is even more preferred.

In the above coupling reaction, the solvent for reacting the compound having the benzobisthiazole structural unit represented by the above formula (1) with the halide of the compound having the bithiophene structural unit represented by the above formula (2) or the halide of the compound having the cyclohexadithiophenedione structural unit represented by the above formula (3) is not particularly limited as long as it does not affect the reaction, and any conventionally known solvent can be used.

This application claims the benefit of priority based on Japanese Patent Application No. 2019-86501, filed on April 26, 2019. The entire contents of the specification of Japanese Patent Application No. 2019-86501 are incorporated herein by reference.

The present invention will be described in detail below with reference to examples. However, the present invention is not limited to the following examples, and modifications can be made within the scope of the above and below-described aims, and all such modifications are within the technical scope of the present invention.

The measurement methods used in the examples are as follows:

(NMR Spectroscopic Measurement)
The NMR spectrum of the compound was measured using an NMR spectrum measuring device ("400MR" manufactured by Agilent (formerly manufactured by Varian)).

Gel Permeation Chromatography (GPC)
The molecular weight of the compound was measured by gel permeation chromatography (GPC). The compound was dissolved in a mobile phase solvent (chloroform) to a concentration of 0.5 g/L, and the measurement was performed under the following conditions. The number average molecular weight (Mn) and weight average molecular weight (Mw) of the compound were calculated by conversion based on a calibration curve created using polystyrene as a standard sample. The GPC conditions in the measurement were as follows.
Mobile phase: chloroform flow rate 0.6 mL/min
Apparatus: HLC-8320GPC (manufactured by Tosoh)
Column: TSKgel (registered trademark), Super HM-H'2 + TSKgel (registered trademark), Super H2000 (manufactured by Tosoh Corporation)

(Synthesis Example 1)
Synthesis of 2,6-bis[5-(2-hexyldecyl)thiophen-2-yl]benzo[1,2-d;4,5-d']bisthiazole (DBTH-HDTH) 2,6-diiodobenzo[1,2-d;4,5-d']bisthiazole (DBTH-DI, 5.2 g, 11.7 mmol), tributyl[5-(2-hexyldecyl)thiophen-2-yl]stannane (HDT-Sn, 23.2 g, 38.6 mmol), tris(2-furyl)phosphine (443 mg, 1.87 mmol), tris(dibenzylideneacetone)dipalladium(0)-chloroform adduct (490 mg, 0.47 mol), and N,N-dimethylformamide (115 mL) were added to a 300 mL flask and reacted at 120°C for 23 hours. After the reaction was completed, the mixture was cooled to room temperature, water was added, and the mixture was extracted twice with chloroform. The organic layer was washed with water and then dried over anhydrous magnesium sulfate. The crude product obtained by filtration and concentration was purified by column chromatography (silica gel, chloroform/hexane=1/1) to obtain 5.62 g of 2,6-bis[5-(2-hexyldecyl)thiophen-2-yl]benzo[1,2-d;4,5-d']bisthiazole (DBTH-HDTH) as a pale yellow solid (yield 60%). ¹ H-NMR measurement confirmed that the target compound was produced.
^1H -NMR (400MHz, _CDCl3 ): δ 8.39 (s, 2H), 7.53 (d, J = 3.6 Hz, 2H), 6.81 (d, J = 3.6 Hz, 2H), 2.81 (m, 4H), 1.66 (m, 2H), 1.37-1.24 (m, 48H), 0.90 (t, J = 6.4 Hz, 6H), 0.88 (t, J = 6.4 Hz, 6H).

(Synthesis Example 2)
Synthesis of 2,6-bis[5-(2-hexyldecyl)thiophen-2-yl]-4,8-diiodobenzo[1,2-d;4,5-d']bisthiazole (DI-DBTH-HDTH) 2,6-bis[5-(2-hexyldecyl)thiophen-2-yl]benzo[1,2-d;4,5-d']bisthiazole (DBTH-HDTH, 4 g, 4.97 mmol) obtained in Synthesis Example 1 above and tetrahydrofuran (80 mL) were added to a 100 mL flask, and the mixture was cooled to -40°C, after which lithium diisopropylamide (2 M solution, 5.5 mL, 10.9 mmol) was added dropwise and stirred for 30 minutes. Next, iodine (3.8 g, 14.9 mol) was added and the mixture was reacted at room temperature for 2 hours. After the reaction was completed, 10% by mass of sodium hydrogen sulfite was added and the mixture was extracted with chloroform. The organic layer obtained was washed with saturated sodium bicarbonate water, then with saturated saline, and dried over anhydrous magnesium sulfate. The crude product obtained by filtration and concentration was purified by column chromatography (silica gel, chloroform/hexane=1/1) to obtain 2.66 g of 2,6-bis[5-(2-hexyldecyl)thiophen-2-yl]-4,8-diiodobenzo[1,2-d;4,5-d']bisthiazole (DI-DBTH-HDTH) as a yellow solid (yield 51%). It was confirmed by ¹ H-NMR measurement that the target compound was produced.
^1H -NMR (400MHz, _CDCl3 ): δ 7.53 (d, J = 3.6 Hz, 2H), 6.81 (d, J = 3.6 Hz, 2H), 2.80 (m, 4H), 1.70 (m, 2H), 1.36-1.24 (m, 48H), 0.89 (t, J = 6.4 Hz, 6H), 0.86 (t, J = 6.4 Hz, 6H).

(Synthesis Example 3)
Synthesis of 2,6-bis[5-(2-hexyldecyl)thiophen-2-yl]-4,8-dithiophen-2-yl-benzo[1,2-d;4,5-d']bisthiazole (DTH-DBTH-HDTH) 2,6-bis[5-(2-hexyldecyl)thiophen-2-yl]-4,8-diiodobenzo[1,2-d;4,5-d']bisthiazole (DI-DBTH-HDTH, 1.1 g, 1.04 mmol) obtained in Synthesis Example 2 above, tributylthiophen-2-yl-stannane (830 μL, 2.60 mmol), tris(2-furyl)phosphine (40 mg, 0.17 mmol), tris(dibenzylideneacetone)dipalladium(0)-chloroform adduct (45 mg, 0.04 mmol), and N,N-dimethylformamide (22 mL) were added to a 50 mL flask and reacted at 80° C. for 19 hours. After completion of the reaction, the mixture was cooled to room temperature, water was added, and the mixture was extracted twice with chloroform. The organic layer was washed with water and then dried over anhydrous magnesium sulfate. Next, the crude product obtained after filtration and concentration was purified by column chromatography (silica gel, chloroform/hexane=1/1 to chloroform) to obtain 1.01 g of 2,6-bis[5-(2-hexyldecyl)thiophen-2-yl]-4,8-dithiophen-2-yl-benzo[1,2-d;4,5-d']bisthiazole (DTH-DBTH-HDTH) as a yellow solid (yield 100%). ¹ H-NMR measurement confirmed that the target compound had been produced.
^1H -NMR (400MHz, _CDCl3 ): δ 8.00 (dd, J = 4.0, 0.8 Hz, 2H), 7.58 (dd, J = 5.2, 0.8 Hz, 2H), 7.55 (d, J = 4.0 Hz, 2H), 7.27 (dd, J = 5.2, 4.0 Hz, 2H), 6.81 (d, J = 4.0 Hz, 2H), 2.81 (m, 4H), 1.72 (m, 2H), 1.34-1.25 (m, 48H), 0.89 (t, J = 6.4 Hz, 6H), 0.87 (t, J = 6.4 Hz, 12H).

(Synthesis Example 4)
Synthesis of 2,6-bis[5-(2-hexyldecyl)thiophen-2-yl]-4,8-bis(5-trimethylstannylthiophen-2-yl)-benzo[1,2-d;4,5-d']bisthiazole (DTH-DBTH-HDTH-DSM) Into a 30 mL flask, 2,6-bis[5-(2-hexyldecyl)thiophen-2-yl]-4,8-dithiophen-2-yl-benzo[1,2-d;4,5-d']bisthiazole (DTH-DBTH-HDTH, 700 mg, 0.72 mmol) obtained in Synthesis Example 3 and tetrahydrofuran (14 mL) were added, and the mixture was cooled to -50°C. Lithium diisopropylamide (2 M solution, 0.79 mL, 1.58 mmol) was added dropwise and stirred for 30 minutes. Then, trimethyltin chloride (1M solution, 16 mL, 1.58 mmol) was added, the mixture was warmed to room temperature, and stirred for 2 hours. After the reaction was completed, water was added and the mixture was extracted twice with toluene. The organic layer was washed with water and then dried over anhydrous magnesium sulfate. The crude product obtained by filtration and concentration was purified by GPC-HPLC (JAIGEL-1H, 2H, chloroform) to obtain 518 mg of 2,6-bis[5-(2-hexyldecyl)thiophen-2-yl]-4,8-bis(5-trimethylstannylthiophen-2-yl)-benzo[1,2-d;4,5-d']bisthiazole (DTH-DBTH-HDTH-DSM) as a yellow solid (yield 55%). It was confirmed by ¹ H-NMR measurement that the target compound was produced.
^1H -NMR (400MHz, _CDCl3 ): δ 8.16 (d, J = 3.6 Hz, 2H), 7.56 (d, J = 3.6 Hz, 2H), 7.37 (d, J = 3.6 Hz, 2H), 6.82 (d, J = 3.6 Hz, 2H), 2.82 (m, 4H), 1.71 (m, 2H), 1.35-1.25 (m, 48H), 0.88 (t, J = 6.4 Hz, 6H), 0.87 (t, J = 6.4 Hz, 6H), 0.47 (s, 18H).

Example 1
Synthesis of P-THDT-DBTH-EH-BTD In a 20 mL flask, 2,6-bis[5-(2-hexyldecyl)thiophen-2-yl]-4,8-bis(5-trimethylstannylthiophen-2-yl)-benzo[1,2-d;4,5-d']bisthiazole (DTH-DBTH-HDTH-DSM, 100 mg, 0.08 mmol) obtained in Synthesis Example 4 and 100 mL of 1,2-dichloro-2,4-diphenyl-2,5-diphenyl-2,6-diphenyl-2,5 ... 1,3-dibromo-5,7-bis(2-ethylhexyl)benzo[1,2-c:4,5-c']dithiophene-4,8-dione (EH-BTD-DB, 47 mg, 0.08 mmol) manufactured by Shuttle, tris(dibenzylideneacetone)dipalladium(0)-chloroform adduct (3 mg, 2.9 μmol), tris(2-methoxyphenyl)phosphine (5 mg, 13.3 μmol), and chlorobenzene (7 mL) were added and reacted at 130°C for 24 hours. After the reaction was completed, the reaction solution was added to methanol (50 mL) and the precipitated solid was collected by filtration, and the obtained solid was washed with a Soxhlet (methanol, acetone, hexane). Then, Soxhlet extraction was performed using chloroform to obtain 90 mg of P-THDT-DBTH-EH-BTD as a black solid (yield 90%). The molecular weight of the obtained black solid was measured by GPC, and the number average molecular weight (Mn) was 13,800 and the weight average molecular weight (Mw) was 22,900.

(Preparation of Mixed Solution 1 of p-type Semiconductor Compound and n-type Semiconductor Compound)
As the p-type semiconductor compound, the polymer compound having the structure of P-THDT-DBTH-EH-BTD obtained in Example 1 above was used, and as the n-type semiconductor compound, PC61BM (phenyl C61 butyric acid methyl ester, manufactured by Frontier Carbon, NS-E100H) was used, and the mass ratio of the p-type semiconductor compound to the n-type semiconductor compound was set to 1:1.5, and the mixture was dissolved in chlorobenzene together with diphenyl ether (0.03 mL/mL). The total concentration of the p-type semiconductor compound and the n-type semiconductor compound was set to 2.0 mass%. The obtained solution was stirred and mixed on a hot stirrer at a temperature of 100°C for 2 hours or more. The solution after stirring and mixing was filtered through a 0.45 μm filter to prepare a mixed solution 1 of the p-type semiconductor compound and the n-type semiconductor compound.

Example 2
Synthesis of P-THDT-DBTH-HD-BTI In a 20 mL flask, 2,6-bis[5-(2-hexyldecyl)thiophen-2-yl]-4,8-bis(5-trimethylstannylthiophen-2-yl)-benzo[1,2-d;4,5-d']bisthiazole (DTH-DBTH-HDTH-DSM, 70 mg, 0.05 mmol), 2,8-dibromo-5-(2-hexyldecyl)-1,9-dithia-5-aza-cyclopenta[e]azulene-4,6-dione (HD-BTI-DB, 34 mg, 0.05 mmol), tris(dibenzylideneacetone)dipalladium(0)-chloroform adduct (2 mg, 2.2 μmol), tris(2-methoxyphenyl)phosphine (3 mg, 8.7 μmol), and chlorobenzene (7 mL) were added and reacted at 130° C. for 24 hours. The HD-BTI-DB was prepared using "Dithieno[3,2-c:2',3'-e]oxepine-4,6-dione (D4972)" manufactured by Tokyo Chemical Industry Co., Ltd. as a raw material, based on the method described in Journal of the American Chemical Society, Vol. 134, pp. 18427-18439, published in 2012.

After the reaction was completed, the reaction solution was added to methanol (20 mL) and the precipitated solid was filtered out and the resulting solid was washed with a Soxhlet filter (methanol, acetone, hexane). Next, Soxhlet extraction was performed using chloroform to obtain 67 mg of P-THDT-DBTH-HD-BTI as a black solid (yield 86%). The molecular weight of the resulting black solid was measured using GPC, and the number average molecular weight (Mn) was 33,500 and the weight average molecular weight (Mw) was 77,400.

(Preparation of Mixed Solution 2 of p-type Semiconductor Compound and n-type Semiconductor Compound)
The polymer compound having the structure of P-THDT-DBTH-HD-BTI obtained in Example 2 was used as the p-type semiconductor compound, and PC61BM (phenyl C61 butyric acid methyl ester, manufactured by Frontier Carbon, NS-E100H) was used as the n-type semiconductor compound, and the mass ratio of the p-type semiconductor compound to the n-type semiconductor compound was 1:1.5, and the p-type semiconductor compound and the n-type semiconductor compound were dissolved in chlorobenzene. The total concentration of the p-type semiconductor compound and the n-type semiconductor compound was 2.0 mass%. The obtained solution was stirred and mixed on a hot stirrer at a temperature of 100°C for 2 hours or more. The solution after stirring and mixing was filtered through a 0.45 μm filter to prepare a mixed solution 2 of the p-type semiconductor compound and the n-type semiconductor compound.

(Fabrication of photoelectric conversion element)
A glass substrate manufactured by Geomatec Co., Ltd. on which an indium tin oxide (ITO) transparent conductive film (cathode) was patterned as an electrode was ultrasonically cleaned with acetone, then ultrasonically cleaned with ethanol, and then dried with nitrogen blow. The dried glass substrate was subjected to UV-ozone treatment, and then an electron transport layer was formed. The electron transport layer was formed by applying a 0.5M zinc acetate/0.5M aminoethanol/2-methoxyethanol solution to the glass substrate with a spin coater (3000 rpm, 40 seconds), and then annealing at 175°C for 30 minutes. The glass substrate on which the electron transport layer was formed was carried into a glove box, and a mixed solution 1 or mixed solution 2 of a p-type semiconductor compound and an n-type semiconductor compound was spin-coated under an inert gas atmosphere, and annealing or reduced-pressure drying was performed on a hot plate to form an active layer. Next, molybdenum oxide, which is a hole transport layer, was evaporated using an evaporation machine. Then, silver, which is an electrode (anode), was evaporated to produce an inverted configuration device.

The photoelectric conversion element of the obtained inverted configuration device was evaluated using a solar simulator according to the following procedure.

(Method of evaluating photoelectric conversion element)
A metal mask of 0.05027 mm square was attached to the photoelectric conversion element, and a solar simulator (OTENTO-SUNIII, AM1.5G filter, radiation intensity 100 mW/cm ² , manufactured by Bunkoukeiki Co., Ltd.) was used as an irradiation light source, and the current-voltage characteristics between the ITO electrode and the silver electrode were measured by a source meter (manufactured by Keithley, Model 2400). From the measurement results, the short-circuit current density Jsc (mA/cm ² ), open-circuit voltage Voc (V), fill factor FF, the value of Voc×FF, and the photoelectric conversion efficiency η (%) were calculated. The short-circuit current density Jsc is the current density when the voltage value is 0 V. The open-circuit voltage Voc is the voltage value when the current value is 0 mA/cm ^2. The fill factor FF is a factor representing the internal resistance, and is expressed by the following formula when the maximum output is Pmax.
FF=Pmax/(Voc×Jsc)
The photoelectric conversion efficiency η is expressed by the following formula.
η=Jsc×Voc×FF

As a result, the inverted configuration device fabricated using the above mixed solution 1 had a Jsc (short-circuit current density) of 5.31 mA/cm ² , a Voc (open-circuit voltage) of 0.96 V, a FF (fill factor) of 0.60, and a Voc×FF value of 0.576. The photoelectric conversion efficiency η was 3.06%. On the other hand, the inverted configuration device fabricated using the above mixed solution 2 had a Jsc (short-circuit current density) of 10.26 mA/cm ² , a Voc (open-circuit voltage) of 0.81 V, a FF (fill factor) of 0.70, and a Voc×FF value of 0.567. The photoelectric conversion efficiency η was 5.82%.

If an organic semiconductor material containing the polymer compound of the present invention is used in an organic electronic device, the product [Voc x FF] of the open circuit voltage (Voc) and the fill factor (FF) of the organic electronic device can be increased, thereby increasing the photoelectric conversion efficiency η. Therefore, the photoelectric conversion efficiency η of organic electronic devices such as organic thin-film solar cells can be increased.

Claims (8)

A polymer compound characterized in that a benzobisthiazole structural unit represented by the following formula (1) and a bithiophene structural unit represented by the following formula (2) or a cyclohexadithiophenedione structural unit represented by the following formula (3) are arranged alternately.

[In formula (1), T ¹ and T ² each independently represent a thiophene ring which may be substituted with a hydrocarbon group or an organosilyl group, a thiazole ring which may be substituted with a hydrocarbon group or an organosilyl group, or a hydrocarbon group, an organosilyl group, an alkoxy group, a thioalkoxy group, a trifluoromethyl group, or a phenyl group which may be substituted with a halogen atom.
Furthermore, B ¹ and B ² each independently represent a thiophene ring which may be substituted with a hydrocarbon group, a thiazole ring which may be substituted with a hydrocarbon group, or an ethynylene group.]

In formula (2), R ^a represents R ^a1 or *-R ^a2 -O-R ^a1 . R ^a1 represents a hydrocarbon group having 6 to 30 carbon atoms, R ^a2 represents a hydrocarbon group having 1 to 5 carbon atoms, and * represents a bond.
Each R ^b independently represents a hydrogen atom or a hydrocarbon group having 1 to 5 carbon atoms.

[In formula (3), R ^c and R ^d each independently represent a hydrocarbon group having 6 to 30 carbon atoms.] 2. The polymer compound according to claim 1, wherein T ¹ and T ² are each independently a group represented by any one of the following formulae (t 3 ) to (t5):

In formulae (t 3 ) to (t5) , R ¹⁵ and R ¹⁶ each independently represent a hydrocarbon group having 6 to 30 carbon atoms or a group represented by *-Si(R ¹⁸ ) ₃ .
R ¹⁷ each independently represents a hydrocarbon group having 6 to 30 carbon atoms, *-Si(R ¹⁸ ) ₃ , *-O-R ¹⁹ , *-S-R ²⁰ , *-CF ₃ or a halogen atom.
n1 represents an integer of 1 to 3, n2 represents 1 or 2, and n3 represents an integer of 1 to 5; multiple R ^15s may be the same or different, multiple R ^16s may be the same or different, and multiple R ^17s may be the same or different.
Each R ¹⁸ independently represents an aliphatic hydrocarbon group having 1 to 20 carbon atoms or an aromatic hydrocarbon group having 6 to 10 carbon atoms, and multiple R ¹⁸ may be the same or different.
R ¹⁹ and R ²⁰ each independently represent a hydrocarbon group having 6 to 30 carbon atoms.
* represents a bond. 3. The polymer compound according to claim 1, wherein B ¹ and B ² are each independently a group represented by any one of the following formulae (b1) to (b3):

In formulae (b1) to (b3), R ²¹ and R ²² each independently represent a hydrocarbon group having 6 to 30 carbon atoms.
n4 represents an integer of 0 to 2, n5 represents 0 or 1, and multiple R ²¹ may be the same or different.
* represents a bond, and the * on the left represents a bond bonded to the benzene ring of the benzobisthiazole structural unit. The polymer compound according to any one of claims 1 to 3, which is a donor-acceptor type semiconducting polymer compound. An organic semiconductor material comprising the polymer compound according to any one of claims 1 to 4. An organic electronic device comprising the organic semiconductor material according to claim 5. The organic electronic device according to claim 6, which is an organic thin-film solar cell. A solar cell module comprising the organic electronic device according to claim 7.